21066260 has 24 divisors (see below), whose sum is σ = 44527560. Its totient is φ = 8371584.

The previous prime is 21066257. The next prime is 21066263. The reversal of 21066260 is 6266012.

It is an interprime number because it is at equal distance from previous prime (21066257) and next prime (21066263).

It can be written as a sum of positive squares in 4 ways, for example, as 1811716 + 19254544 = 1346^2 + 4388^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21066263) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 215 + ... + 6494.

It is an arithmetic number, because the mean of its divisors is an integer number (1855315).

Almost surely, 2^21066260 is an apocalyptic number.

21066260 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21066260 is an abundant number, since it is smaller than the sum of its proper divisors (23461300).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21066260 is a wasteful number, since it uses less digits than its factorization.

21066260 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6875 (or 6873 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 21066260 is about 4589.7995598937. The cubic root of 21066260 is about 276.1822817436.

The spelling of 21066260 in words is "twenty-one million, sixty-six thousand, two hundred sixty".